We'll be on Grand Princess in a little more than two weeks, also Western Caribbean. I would suggest reading as many cruise bulletin boards and cruise reviews as possible. You can learn so much, it's amazing. Then if you have specific questions, post them here or maybe on a couple of boards.
Besides this fine website, check out cruiseopinion.com for reviews. cruise-addicts.com and cruisecritic.com for bulletin boards and passenger reviews.